Cause of Rolling Contact Fatigue Cracks in Curved Switch Rail of High- speed Turnout

Abstract:

According to the designed and the measured stock and curved switch rail profiles of the No. 18 high-speed single-way turnout， a vehicle-turnout dynamic model was established to analyze the wheel loading position transfer， normal contact stress in the stock and curved switch rails and their fatigue damage indexes during train passing turnout along reverse and side direction. The reason that the fatigue crack in curved switch rail was presented. The results show that the switch rail machined depth to the stock rail was not as enough as the standard one which made the loading position transferred early and rapidly for the outer wheels of both the front and rear wheelsets in the same bogie respectively. With the wear’s coming into being between the wheel and rail profiles， this situation got worse. Then， large normal contact stress occurred in the curved switch rail especially by the outer wheel of the front wheelset in the bogie which contributed the most to the rolling contact fatigue crack at the gauge shoulder and corner of the curved switch rail. The fatigue crack would appear first in the curved switch rail with the top width of about 20 ~ 50 mm.

Key words:high-speed railway;turnout;switch rail;rolling contact fatigue;wheel-rail contact